Various liquids which are shipped in bulk containers are exposed to conditions which adversely affect the level of purity of these liquids. In many situations the maintenance of high purity is necessary for the practical acceptance of the liquid. As an example, in semiconductor applications it is essential that chemicals of high purity be used in various processing steps; otherwise the resulting product is not acceptable. The sources of contamination for these bulk liquids may be introduced at various stages such as when the bulk container is filled or when the liquid in the bulk container is withdrawn and, particularly, when only a part of the liquid is withdrawn and the bulk container is recapped to preserve the balance of the contents for a subsequent use. In such cases the contaminant may be introduced by the contaminated fittings or from a filter elements which are contaminated or even by ambient or other gas air which displaces the amount of liquid withdrawn from the container. In some instances a liquid in the replenishing bulk container is less than the desired purity due to the original relatively low purity level or because the product has been subsequently exposed to contaminants. It is, therefore, important that this purity be upgraded without requiring that the product be returned to the packaging source for reprocessing or otherwise upgrading of the purity.
An additional problem of contamination and often considerable delay arises when the spent liquid bath is to be replaced with fresh liquid A considerable contamination exposure, for example, is introduced during the uncoupling and re-coupling of fittings in the system during the replacement of the spent high purity treating liquid.
It is apparent, accordingly, that a need exists for a bulk packaging purification and delivery system that provides for maintaining a high level of purity of the product in a bulk liquid container and for facilitating the upgrading of the purity of the liquid in the container.